In general, a cage is provided between an outer ring and an inner ring of a rolling bearing so that rolling elements are held with a predetermined interval along a circumferential direction thereof. For example, FIG. 9 is a sectional diagram showing a rolling bearing using a general cage having a crown shape. The cage 114 includes an annular portion 119 of an annular shape and a pillar portion 120 which protrudes toward the same direction from one side surface in the axial direction (left side) of the annular portion 119, whereby a housing space (pocket) 121 for housing a rolling element 117 between the pillar portions 120 adjacent to each other in the circumferential direction is formed. The pocket 121 is opened at the one end side (a side in opposite to the annular portion 119 side) in the axial direction of the cage 114. The cage 114 is configured to have an asymmetrical shape in the left and right direction with respect to the center in the axial direction of the rolling bearing 110.
Further, JP-A-2003-232362 discloses a technique in which many narrow grooves are formed on the inner peripheral surface and the outer peripheral surface of a crown-shaped cage along the circumferential direction thereof to thereby rectify the flow of peripheral lubricant to reduce fluid loss.